1. Technical Field
The present disclosure relates to an on-vehicle structure for a power control unit that drives a motor for traveling (traveling motor).
2. Description of Related Art
A vehicle that travels by using an electric motor includes a power control unit for driving the electric motor. Noted that a technique disclosed in this specification is not limited to application to an electric vehicle but can also be applied to a hybrid vehicle and a fuel cell vehicle. In addition, for simplification of the description, the “electric motor” will simply be described as a “motor”.
The power control unit is typically an inverter that converts DC power output by a DC power supply to AC power. The power control unit possibly includes a booster converter. Several types of vehicles, in which the traveling motor is provided, include the motor and the power control unit in a front space (an engine compartment) of the vehicle. In this specification, according to a custom in a technical field of an automobile, a space for housing a traveling motor is described as “engine compartment” regardless of whether an engine is actually mounted or not.
The power control unit is possibly fixed above a housing of the motor. By arranging the power control unit near the motor, a power cable that connects the power control unit and the motor is shortened, and thus loss in power transmission can be suppressed. One example of such an on-vehicle structure for the power control unit is disclosed in Japanese Patent Application Publication No. 2013-233836 (JP 2013-233836 A). In a technique disclosed in JP 2013-233836 A, in order to protect the power control unit from vibrations of the motor, a front portion and a rear portion of the power control unit are respectively supported by a front bracket and a rear bracket, and the power control unit is fixed with a space being formed above the housing.
Components that handle power of tens of kilowatts exist in the power control unit. The power control unit is desired to be high in collision safety so that a high-voltage circuit therein is not exposed during a collision of the vehicle. A device that is arranged in the front space of the vehicle possibly receives a significant shock when the vehicle is involved in a frontal collision. Meanwhile, the housing of the motor is relatively large and rigid. Thus, arrangement of the power control unit above the housing of the motor is also suited for protection of the power control unit from an obstacle that approaches from the front during the collision. Despite such arrangement, depending on a case, a collision shock possibly hits the power control unit, which is fixed above the housing, during the collision. For example, there is a case where the vehicle is involved in the frontal collision with the obstacle at a high speed. Alternatively, in a collision aspect in which only a front right portion (or a front left portion) of the vehicle collides with the obstacle instead of the frontal collision of the vehicle with the obstacle, the obstacle possibly enters deep inside the front space of the vehicle, and the device arranged in the front space possibly receives a significant collision load. Noted that the collision aspect in which only the front right portion (or the front left portion) of the vehicle collides with the obstacle is called an overlap collision (or an oblique collision) and the like. The overlap collision will be described again in the section of the detailed description of embodiments.